1. Technical Field
The disclosure relates to an image sensor configured to image a subject to generate image data of the subject. The disclosure also relates to an imaging device, an endoscope, and an endoscopic system.
2. Related Art
Conventionally, image sensors such as a CMOS (Complementary Metal-Oxide Semiconductor) image sensor hold an image signal transferred row by row using a sample-and-hold circuit, sequentially output the image signal to a horizontal output signal line for each pixel using column reading circuit, and perform reading of the image signal. In such image sensors, a technique has been known which provides a reference voltage generator to generate a reference voltage signal in the image sensor and acquires a difference between the reference voltage signal and an image signal using an analog front end circuit (hereinafter, referred to the “AFE circuit”) provided outside the image sensor in order to reduce a fixed pattern noise of an image sensor (see JP 2007-159115 A).